/Engine/Source/Runtime/Experimental/GeometryCollectionEngine/Public/GeometryCollection/GeometryCollectionEngineConversion.h
TODO: consider having the below fn return bool, and have a helper that returns the StartMaterialIndex fromUGeometryCollectionbefore any materials are actually added, so we can call the AppendMaterial function after, and not need to use its return value ... This would let the is-there-a-valid-mesh logic live inside this function NOTE: and similar change will need to propagate to similar places ... Appends a static mesh to a GeometryCollectionComponent.
true if succeeded in appending a mesh
static bool AppendStaticMesh ( const [UStaticMesh](API\Runtime\Engine\Engine\UStaticMesh) * StaticMesh, int32 StartMaterialIndex, const FTransform & StaticMeshTransform, [FGeometryCollection](API\Runtime\Chaos\GeometryCollection\FGeometryCollection) * GeometryCollection, bool bReindexMaterials, bool bAddInternalMaterials, bool bSplitComponents, bool bSetInternalFromMaterialIndex )